Organo phosphite and nickel complex uv light stabilizer system

ABSTRACT

The effectiveness of nickel amine complexes of bis-phenol sulfides as ultraviolet light stabilizers for polymers is enhanced by the further presence of a small amount of a phosphite extended t-alkylated bisphenol A.

Siates Mathis et a].

atei [191 [451 Aug. 28, 1973 1 ORGANO PHOSPl-IITE AND NICKEL COMPLEX UV LIGHT STABILIZER SYSTEM [75] Inventors: Ronald D. Mathis, Taylors; James S.

Dix, Greenville, both of S.C.

[73] Assignee: Phillips Petroleum Company,

Bartlesville, Okla.

[22] Filed: Jan. 10, 1972 [21] Appl. No.: 216,741

[52] US. Cl.. 260/4515 N, 252/401, 260/4595 D [51] Int. Cl. (108145/62 [58] Field of Search 260/4575 N, 45.95 D;

[56] References Cited UNITED STATES PATENTS 3,167,526 1/1965 Nicholson 260/457 3,412,064 11/1968 Brindell 260/4595 3,379.680 4/1968 OKonski 260/4575 3,655,718 4/1972 Schutze et al. .1 260/4595 Primary ExaminerDonald E. Czaja Assistant Examiner-V. P. Hoke Attorney- Quigg 8L Oberlin [57] ABSTRACT 10 Claims, No Drawings ORGANO IIIOSPI-IITE AND NICKEL COMPLEX UV LIGHT STABILIZER SYSTEM FIELD OF THE INVENTION This invention relates to methods to improve the effectiveness of nickel amine complexes as ultraviolet stabilizers for polymers. It further relates to improved stabilized polymer compositions.

Many polymers are subject to deteriorative action of ultraviolet light and hence need effective stabilization for satisfactory service life. Ultraviolet light tends to cause, for example, severe losses of tenacity in fibers, and early development of embrittlement in films, sheets and the like. Nickel complexes, such as those of the thiobisphenols or bis-phenol sulfides, have been widely used as ultraviolet light stabilizers for various polymers. However, to produce polymers of sufficient service life to be commercially acceptable and competitive requires still further improvement in stabilization against the deteriorative effects of ultraviolet light.

SUMMARY OF THE INVENTION We have discovered that certain organophosphite type additives exercise a surprising degree of assistance to nickel complexes in stabilizing polymers against deteriorative effects of ultraviolet light.

More particularly, the organophosphites which are phosphite extended t-alkylated bisphenol A compounds improve to a surprising degree of effectiveness of nickel amine complexes for polymer stabilization.

It is an object of our invention to improve the effectiveness of nickel complexes in stabilizing polymers. It is' a further object of our invention to provide improved stabilized polymer compositions.

DETAILED DESCRIPTION OF THE INVENTION Our invention lies in the improved stabilization of polymers by the use of a combination of a nickel complex together with an organophosphite, particularly a phosphite extended t-alkylated bisphenol A.

The organophosphite additives can be represented by:

tive to enhance the effectiveness of the nickel complex. Such an amount broadly will be in the range of from about 0.01 to 1.0 parts of our additive per 100 parts polymer, php, excluding nickel complex, and excluding other additives often added to polymeric compositions for a variety of purposes as known to the art. Either a single organophosphite additive can be used, or mixtures of two or more.

The weight ratio of nickel complex to organophosphite additive can vary broadly, such as over about 20:1 to 111, preferably 15:] to 2:1. The total amount of nickel complex plus organophosphite additive used in the polymer for stabilization can vary widely. From about 0.03 to 5 parts of stabilizer system will be effective per 100 parts of polymer, excluding other additives normally added to the polymers.

Any nickel complex known to the art as a polymer ultraviolet light stabilizer can be improved when used in combination with our organophosphite additive. Frequently used as stabilizers are the nickel amine complexes of bis-phenol sulfides, sometimes termed nickel complexes of thiobis-phenols. More particularly, such nickel complexes are nickel amine complexes of the 2,2-thiobis-4-alkylphenols. A single nickel complex can be used, or two or more. A presently preferred nickel amine complex is 2,2-thiobis-4-t-octyl-phenol complex with n-butylamine in a l:l molar ratio, [2,2- thiobis(4-t-octyl-phenolato)l n-butylamine nickel (ll).

Such nickel complexes are prepared by reacting the nickel salt of 2,2'-thiobis-p-alkylphenol, wherein the alkyl radical can be cyclic or can be an open chain moiety, preferably as the 1:1 aquo complex with a suitable amine in an inert volatile organic solvent, such as benzene, chloroform, either, acetone, and the like. The solvent can be removed by conventional means, leaving a substantially pure solid nickel amine complex. The 2,2'-thiobis-p-alkylphenols themselves are well known compounds and can easily be prepared by known means such as reaction of a p-alkylphenol with such as SCl The desired 1:1 aquo complexes are prepared by reacting a nickel salt with 2,2-thiobis-p-alkylphenol in wherein each R, R, and R", is hydrogen or hydrocarby], and where hydrocarbyl is alkyl, cycloalkyl, aryl, aralkyl, and alkaryl, containing up to 20 carbon atoms per each such group. The several groups can be alike or can each differ one from the other. The number of R groups per ring can vary from 0 to 4. The structure indicated by the brackets in the formula above can be repeated such that the integer n can range from 1 to about 5.

The presently preferred organophosphite is one in which R is t-butyl, n l, and R and R" each is a methyl group. The preferred structure can be made by extending bisphenol A, i.e., p,pisopropylidenediphenol, with a phosphorous compound such as dichlorophosphorous acid. A transesterification reaction can be used between a dialkyl phosphite such as dimethyl phosphite and bisphenol A or substituted bisphenol A to produce additives of our invention.

The amount of the organophosphite additive used according to our invention is that amount which is effecdecylamine; primary aromatic amines such as aniline,

anisidine, toluidine, l-naphthylamine, 2- naphthylamine, p-dodecylaniline, p-butylaniline, xylidene and p-octyloxyaniline; and cyclic secondary amines such as morpholine, hexamethyleneimine, piperazine and piperidine. The amines also may contain a hydroxyl group such as is exemplified by triethanolamine and the like.

Nickel complexes are used for the stabilization of polymers over a broad concentration, though in minor amount relative to the amount of polymer. Such a broad range can be from about 0.02 to 2.5 php, more usually from 0.2 to 2 php, parts of nickel complex per 100 parts of polymer excluding other additives.

The stabilizers themselves, the organophosphite additive and the nickel complex, can be incorporated or mixed with the polymers by any suitable method known to the art for incorporating additives or additive combinations into polymeric materials.

For example, the stabilizers can be incorporated into polymer formulations by dry-blending with polymer powders or pellets such as in tumble mixers, Henschel mixers, and the like. This can be followed by additional mixing in a screw extruder, Banbury mixer, Brabender mixer, roll mills, etc., and the like, to blend the stabilizers with a molten polymer or polymeric product.

The stabilizers can be sprayed onto a polymer powder from a solution or dispersion such as from acetone, methanol, cyclohexane, aromatic hydrocarbon such as benzene, and the like, prior to pelletizing of the polymeric composition such as by extrusion. Solvent used for such dispersions usually is removed by evaporation from the treated polymer prior to extrusion. However, it is feasible to extrude the solvent-wetted polymerstabilizer admixture using such as a devolatilizing extruder so as to remove the solvents as vapors.

Certainly, conventional additives such as fillers, pigments, fibers, reinforcements, other stabilizers of various types, plasticizers, thermal stabilizers such as the hindered phenols sold in the trade as Irganox I076 octadecy1[3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate, and Irganox 1010 tetrakis[methylene(3,S-di-tertbutyl-4-hydroxyhydrocinnamate) ]methane; 2,6-ditert-butyl-4-methylphenol known as BHT; thio-dipropionic acid esters such as dilauryl thiodipropionate and distearyl thiodipropionate; other processing aids such as calcium stearate, and the like, all can be incorporated as desired with the polymers for various purposes and by methods known to the art.

The protective system we have developed for protecting polymers is employed with normally solid polymers, including homopolymers, copolymers, belnds of a variety of two or more polymers or copolymers, such as polymers of the aliphatic l-olefins, the polystyrenes and other poly(vinyl-substituted aromatic compounds), po1y(viny1 halides) such as poly(vinyl chloride), poly(vinylacetate)s, polyamides, polyesters, and the like, in which nickel complexes are used as stabilizers.

Polymers of the l-olefins include those in general of the l-monoolefins having from two to eight carbon atoms per molecule, include homopolymers of such as ethylene, propylene, or octene, copolymers of two or more such l-olefins, blends or mixtures of two or more polyolefins, and the term includes copolymers of one or more l-monoolefin copolymerized with other monomers copolymerizable therewith such as are well known in the polymer arts. Polymers of l-monoolefins can be prepared by means known to the art, such as is disclosed by J. P. Hogan et al in United States Letters Patent No. 2,825,721, or by C. W. Moberly in the United States Letters Patent No. 3,403,140. Polymers of vinyl-substituted aromatic compounds usually are prepared from monomers of up to about 12 carbon atoms per molecule, although larger monomers molecules are often used. Methods of preparing such polymers, and others described above, are well known in the polymer arts.

EXAMPLES Illustrative of the scope of our invention, and without intending to be limitative in any manner, are runs which illustrate the unique and surprising nature of effectiveness of our organophosphites as we have discovered them in use in conjunction with nickel complexes.

Various combinations of a nickel ultraviolet stabilizer with and without our organophosphites and with other types of organic phosphites, were added to polymers in order to determine effectiveness as ultraviolet light stabilizers.

The polymer used in the runs was a polyolefin, a polypropylene, and was prepared by conventional means by polymerizing propylene by means of a stereospecific catalyst system, TiCl -l/3 AlCl and diethylaluminum chloride, to give a substantially crystalline polymer containing less than about 5 per cent amorphous polymer. The melt flow ofthe polypropylene was about 12 (ASTM D 1238-62T Condition L), its density was about 0.905 g/cc, and its melting point (determined optically) was about 340 F. The polymer contained conventional commercial additives such as antioxidant and processing aid.

The polymer formulations contained about 0.96 per cent, based on fiber weight, of fast red BR FPP as colorant. The fast red BR FPP was contained in D-1333, a colorant/polypropylene masterbatch containing 25 weight per cent colorant and sold by Imperial Color & Chemical Department of Hercules, Inc. In actual practice, the masterbatch was let down with enough of the basic resin formulation so that this final blend contained the various ingredients as previously enumer-' ated. Crimped tow was prepared from fiber melt spun from the fonnulations.

The nickel complex used as exemplary was [2,2'- thiobis(4-t-octyl-phenolato)]n-buty1amine nickel (11), representative of a type of complex commonly used as an ultraviolet light stabilizer in many polymers. This nickel complex was used alone, or with various phosphite additives.

All tests were run in a modified Weather-Ometer with the treated polyolefin utilized being in the form of a 4,000 denier (18denier per filament) scarlet crimped tow. Values reported are in the time in hours to decrease tenacity to 1 gpd.

TABLE I Weather Nickel Phosphite Ometer Run No. stabilizer Additive Results (p p) p I 1.2 None 430 2 1.2 0.1 organophosphite 545 3 1.2 0.5 organophosphite 505 4 1.6 None (b) 575 5 1.6 0.3 organophosphite 680 6 1.6 0.1 phenyldidecyl phosphite 560 7 1.6 0.3 phenyldidecyl hosphite 550 a php parts by weight per parts of polymer. b Phosphite extended t-butylated bisphenol A, as described hereinabove wherein n l.

The tests tabulated above show by Runs 2, 3 and 5, the sharp effectiveness of our organophosphites in increasing the protection obtainable by the niekel complex according to our invention. Furthermore, the com- 5 6 parison in the last two runs, Runs 6 and 7 above, clearly to amine molar ratio of 1:1; and show the complete non-effectiveness, even harmful efb. an organophosphite represented by the formula:

fir? 5' 1 no -r --o i'-oc --on R L i1 D-l Row Ro-r Rn-i H fect, of other commercially available organic phoswherein each R, R, and R contains up to 20 carbon phites in combination with the nickel complexes. atoms and is individually selected from hydrogen, alkyl,

Futther comparative runs were made with additional cycloalkyl, aryl, aralkyl, and alkaryl; the number of commercially organic available phosphites, using the groups per ring is to 4; and n is an integer of l to procedure as described in Example I, with the following the weight ratio of component (a) to component (b) results: being within the range of to 1:1.

TABLE I1 2. The composition of claim 1 wherein component (a) is [2,2'-thiobis(4-t-0ctyl-phenolato)]n-butylamine nickel (ll).

3. The composition of claim 1 wherein, in the or- Weather 20 Nickel phosphite Omem ganophosphite, R 18 t-butyl, there 15 one R group per -P Additive Resul's ring, each R and R is methyl and n is l. The followings were 25 on scarlet 4. The composition of claim 3 wherein the nickel p d tw amine complex is [2,2-thiobis(4-t-octyl-phenolato)1ng S 417 butylamine nickel (II).

. loctylphosphite 420 10 1.2 0.3 dioctyl phosphite 395 5. A stabilized polyolefin composltlon comprising a i; g g pentaerythfiml 2;; polymer of an aliphatic l-olefin stabilized with a mixdiphosphite ture of a. 0.02 to 2.5 parts by weight per hundred parts of iggggg amig fi figg gggi the polymer of a nickel amine complex of a 2,2- same as the scarlet low described above thlob1s( 4-alkylphenol) wherein the complexi P l l g 1 weight per cem forming amine is a member selected from the tltanium dioxide in place of the red colorant. 13 (H diocty] phosphile 830 group consisting of ammonia, primary aliphatic l4 9- hydfgenamd 950 amine, primary aromatic amine and cyclic secondphosphite ary amine and said nickel complex and said amine are present in a molar ratio of 1:1; and The following were made on a 5 milfilm b. 0.01 to 1 parts by weight per hundred parts of :2 8:; gf'fi 32g polymer of an organophosphite represented by the phosphite formula:

It" L I. t J

Runs 2, 3 and 5 above showing results of our organowherein each R, R, and R" contains up to 20 carbon phosphite-nickel complex combination stabilizer sysatoms and is individually selected from hydrogen, alkyl, tem according to our invention conclusively demoncycloalkyl, aryl, aralkyl, and alkaryl; the number of strate the high degree of effectiveness. Various other groups per ring is 0 to 4; and n in an integer of l to 5. types of organic phosphites either produce little benefi- 6. The composition of claim 5 wherein the polyolefin cial effect, or for the most part even decrease effectiveis a homopolymer or copolymer of an aliphatic lness of the nickel complexes. monoolefin having from two to eight carbon atoms per Reasonable variations and modifications of our inl ul vention are possible within the scope of our disclosure, 7. The composition of claim 6 wherein said polymer without departing from the spirit and scope thereof as is a polymer of propylene. disclosed in the specification hereinabove and the 8. The composition of claim 5 wherein component claims hereinafter. (a) is [2,2-thiobis(4-t-octyl-phenolato)]n-butylamine We claim: nickel ([1).

LA composition of matter useful for stabilizing poly- 9, Th composition f l i 5 h i i h op mers which Comprises a mixture 0 ganophosphite, R is t-butyl, there is one R group per a. a nickel amine complex of a 2,2-thiobis(4- ring, each R and R" is methyl and n is l.

y p wherein the complex-forming amine 10. The composition of claim 9 wherein the polyoleis a member Selected from the group consisting of fin is a polymer of propylene and the stabilizer is [2,2'- ammonia, primary aliphatw amines, p y thiobis(4-t-octyl-phenolato)]n-butylamine nickelu matic amines and cyclic secondary amines, said complex being characterized by a nickel complex a s a: x 

2. The composition of claim 1 wherein component (a) is (2,2''-thiobis(4-t-octyl-phenolato))n-butylamine nickel (II).
 3. The composition of claim 1 wherein, in the organophosphite, R is t-butyl, there is one R group per ring, each R'' and R'''' is methyl and n is
 1. 4. The composition of claim 3 wherein the nickel amine complex is (2,2''-thiobis(4-t-octyl-phenolato))n-butylamine nickel (II).
 5. A stabilized polyolefin composition comprising a polymer of an aliphatic 1-olefin stabilized with a mixture of a. 0.02 to 2.5 parts by weight per hundred parts of polymer of a nickel amine complex of a 2,2''-thiobis(4-alkylphenol) wherein the complex-forming amine is a member selected from the group consisting of ammonia, primary aliphatic amine, primary aromatic amine and cyclic secondary amine and said nickel complex and said amine are present in a molar ratio of 1:1; and b. 0.01 to 1 parts by weight per hundred parts of polymer of an organophosphite represented by the formula:
 6. The composition of claim 5 wherein the polyolefin is a homopolymer or copolymer of an aliphatic 1-monoolefin having from two to eight carbon atoms per molecule.
 7. The composition of claim 6 wherein said polymer is a polymer of propylene.
 8. The composition of claim 5 wherein component (a) is (2,2''-thiobis(4-t-octyl-phenolato))n-butylamine nickel (II).
 9. The composition of claim 5 wherein, in the organophosphite, R is t-butyl, there is one R group per ring, each R'' and R'''' is methyl and n is
 1. 10. The composition of claim 9 wherein the polyolefin is a polymer of propylene and the stabilizer is (2,2''-thiobis(4-t-octyl-phenolato))n-butylamine nickel (II). 